The proposed work will involve a study of human blood platelets with special reference to the role of platelet mitochondria in platelet survival and function. Platelets will be separated by several procedures according to age, and various parameters then investigated. These will include function tests, oxidative metabolism as well as direct composition. Platelets will also be disrupted for releasing their subcellular organelles, following which mitochondrial fractions will be characterised. It is also planned to investigate platelets from patients with platelet bleeding disorders.